Form-fill-seal machine

ABSTRACT

Form-fill-seal machine includes parts for moving a web of packaging material through the machine according to a process path and parts for transforming the web into filled bags, as well as a zipper strip applicator device for supplying a zipper strip for each bag transverse to the process path, by use of a first and a second conveyor, which in the supply direction of the zipper strip are placed one behind the other and are both provided with parts for retaining the zipper strip during supply, a blade being placed between the first and the second conveyor for cutting the zipper strip and the first and the second conveyor being provided with their own first and second drive.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a division of co-pending application Ser. No.09/985,037, filed on Nov. 1, 2001, the entire contents of which arehereby incorporated by reference.

FIELD OF THE INVENTION

[0002] The invention relates to a form-fill-seal machine, particularly aform-fill-seal machine wherein a web of bag material, such as foil,before transforming it into a tubular shape, is provided with so-calledzipper strips, one for each bag to be made/filled. Said zipper stripsgenerally consist of two strip members situated opposite each other andprovided with male and female parts that can be brought into detachableengagement with each other, are taken from a stock and are appliedtransverse to the web, either with or without a limited pre-weld orpre-adhesion. In the action of transverse sealing the bags, the zipperstrip is also permanently welded to the bag walls.

BACKGROUND OF THE INVENTION

[0003] From U.S. Pat. No. 4,617,683 it is known to apply a zipper stripprovided with adjacent male and female parts, over the full width of aweb of bag material, by engaging a leading area with a vacuum head andmoving the head transverse over the upper side of the web to the otheredge. Subsequently the zipper strip is welded to the web by means of athermal seal rod extending from above and an anvil. Alternatively thezipper strip may be provided with a heat activated glue.

[0004] From U.S. Pat. No. 4,878,987 it is known to supply thecooperating male and female parts of the zipper strip from both sides,transverse to the web, by means of pusher rolls. The male and femalestrips are then each pushed from their side towards the centre, guidedby transverse ducts, and then welded to the web.

[0005] From the international patent application WO 98/03328 it is knownto place a zipper strip transverse to the web of bag material by meansof a vacuum band positioned above the web and weld the strip to the bagmaterial.

[0006] Applying the zipper strips requires a high control of theorientation and the exact location of the strips, as imperfections in itmay hinder the further process and may result in malfunctioning.

OBJECT OF THE INVENTION

[0007] It is an object of the invention to provide a form-fill-sealmachine of the type mentioned in the preamble with which a very highdegree of control can be achieved in placing the zipper strips.

[0008] It is a further object of the invention to provide aform-fill-seal machine of the type mentioned in the preamble, with whicha high processing speed can be realised of high accuracy.

SUMMARY OF THE INVENTION

[0009] From one aspect the invention to that end provides aform-fill-seal machine comprising means for moving a web of packagingmaterial through the machine according to a process path and means fortransforming the web into filled bags, furthermore comprising a zipperstrip applicator device having means for supplying a zipper strip foreach bag transverse to the process path, which supply means comprise afirst and a second conveyor, which in the supply direction of the zipperstrip are placed one behind the other and are both provided with meansfor retaining or engaging the zipper strip during supply, a cuttingmeans such as a blade being placed between the first and the secondconveyor for cutting the zipper strip and the first and the secondconveyor being provided with their own first and second drive means.

[0010] The division into two conveyors makes it possible to dividefunctions as well, and namely a supply function for the first conveyorand a positioning function for the second conveyor, the zipper stripeach time being held over his length by the first and/or secondconveyor.

[0011] Preferably the machine is provided with control means for thefirst and second drive means and the blade, the control means beingadjusted to consecutively operate the first drive means to transfer apredetermined length of zipper strip to the second conveyor, tosubsequently operate the blade and then operate the second conveyor forpositioning the cut-off zipper strip portion transverse to the web.

[0012] Preferably the control means are adjusted to let both conveyorsmove at the same speed during the supply of the length of zipper strip.

[0013] It is preferred here that the retaining means of the first andthe second conveyors as well are controlled by the control means,preferably for continuously activating them. They may be designed asvacuum band means—known per se—. In view of efficiency of the suctionand creating as few as possible process disrupting air flows, it isadvantageous when the machine is provided with means for adjusting theactive length of the vacuum means for the second conveyor. Preferablythe control means are then provided with means for comparing an enteredzipper strip length and the position in transverse direction to the weband the adjusted length of the vacuum means, and of means for releasingthe drive of the machine based on the outcome of said comparison. Whenthe length of the vacuum means does not correspond to the one necessaryfor the process in question the machine will not be released.

[0014] The means for adjusting the active length of the vacuum meanspreferably comprise a tube to be connected to a vacuum source, whichtube in its circumference is provided with series of apertures ofdifferent length extending in tube direction, and which is rotatable inan adjustable manner to let a selected series of apertures form theconnection between the apertures in the vacuum band and the tube.

[0015] It is further preferred that at least the second conveyor isplaced below the web.

[0016] This improves the stability of the zipper strip.

[0017] The controllability of the zipper strip is further improved whenthe machine is furthermore provided with means for guiding the zipperstrip on the first and/or second conveyor, which guiding means arepreferably formed by a rigid guiding strip, which is positioned toextend between the male and female parts of the zipper strip. In thisway the zipper strip is guided in sideward direction, so that it isprevented that it would want to run off from the conveyors as a resultof its natural inclination to warp in the main plane.

[0018] Preferably the guiding strip is interrupted, and it isparticularly formed by a series of teeth, so that frictional forces,that may counteract a smooth supply of the zipper strip, are limited toa minimum. The guidance is improved when the teeth have inclined sideedges and/or rounded tips.

[0019] As a result of the interrupted guidance, in particular the teeth,the negative effects of the undulation in the zipper strip, whichundulation is the result of the rolled-up position in which the zipperstrip material is supplied, is further reduced, because of reduction ofthe friction and the guidance in the vertical plane. As a result thegrip of the retaining means, particularly the vacuum means is improved.

[0020] Preferably the guiding strip is positioned to—considered inprocess path-engage the upstream side of the zipper strip, between thestrip members having the male and female parts.

[0021] In a further development the zipper strip applicator device isalso provided with an anvil strip for use in the pre-sealing of thezipper strip to the web, which anvil strip then is preferably situatedat the—considered in process path-downstream side of the secondconveyor. The applicator device here also provides a counter forceduring the pre-sealing.

[0022] In a further development the zipper strip applicator device issupported on an auxiliary frame, which itself is supported in a mainframe of the machine, the auxiliary frame with respect to the main framebeing moveable between a retracted operative position and an extendedadjustment position. The initial insertion of the zipper strip can thentake place in an easily accessible manner. It is preferred here that acalibration is provided on the second conveyor, extending along theretaining means, preferably starting at the location of the blade.

[0023] When the machine is further provided with control means that havebeen provided with means for noticing the operative position of theauxiliary frame and with means for releasing the drive of the machinebased on that observation, it is ensured that only in case of a correctposition of the auxiliary frame and thus of the applicator device themachine can start running.

[0024] From a further aspect the invention provides a form-fill-sealmachine comprising means for moving a web of packaging material throughthe machine according to a process path and means for transforming theweb into filled bags, further comprising a zipper strip applicatordevice having means for supplying a zipper strip for each bag transverseto the process path, which zipper strip applicator device is supportedon an auxiliary frame, which itself is supported in a main frame of themachine, the auxiliary frame with respect to the main frame beingmoveable between a retracted operative position and an extendedadjustment position.

[0025] From another aspect the invention provides a form-fill-sealmachine of the type described in the preamble, further provided withcontrol means having means for noticing the position of a longitudinaledge of the web with respect to a fixed reference in the machine. Thisalso provides a condition for further optimizing the accuracy of theplacement of the zipper strip. It may also be possible in this way toinfluence the position in transverse direction of the web with respectto the form shoulder.

[0026] In a further development hereof the machine is also provided withmeans for positioning the zipper strip applicator device in transversedirection, in response to the data from the edge noticing means. By thuswatching the position of the web side and automatically correcting theposition of the applicator, errors in the width-positioning of thezipper strip with respect to the web edge as a result of sidewardmovement of the web is prevented. The means for positioning the zipperstrip applicator device in transverse direction may be formed by aservo-driven spindle motor.

[0027] In another further development the control means are adapted tocontrol the drive of in particular the second conveyor in the movementof the zipper strip to be applied, in response to the data from the edgenoticing means.

[0028] From yet another aspect the invention provides a form-fill-sealmachine of the type described in the preamble, furthermore provided withcontrol means having first means for noticing longitudinal marks on theweb and for measuring the web distance travelled over a certain periodby the web at that location, which are placed near the zipper stripapplicator device, at least for the noticing means at a distance from itknown to the control means, the control means being adapted to controlthe drive(s) of the zipper strip applicator device, such as the saidfirst and second conveyor, in response to the data from the first meansfor noticing longitudinal marks on the web and for measuring the webdistance.

[0029] From a further aspect the invention provides a form-fill-sealmachine of the type mentioned in the preamble, furthermore provided withcontrol means having first means for noticing longitudinal marks on theweb and for measuring the web position, which are placed near the zipperstrip applicator device, wherein downstream of said first means themachine is provided with an end roll for the web, which is movablyarranged on the machine and which can be adjusted in position withrespect to the web course by means of movement means, the control meansbeing adapted for controlling the movement means of the end roll foraltering the web length between the first means and the transversesealing means, in response to the data from the first means for noticinglongitudinal marks on the web and the measuring of the web position. Theend roll may be automatically moved, for instance by sliding or turningaway, to increase or reduce the web length between zipper stripapplicator device and transverse sealing unit/cutting unit. In this wayan accurate placement of the zipper strip with respect to the tracerspot and the transverse seam is ensured again and again.

[0030] Preferably the control means are provided with means for storageof data regarding the bag length, the distance between the noticingmeans and the pre-seal unit for the zipper strip, the distance betweenthe longitudinal mark and the transverse seam of a bag made and thedistance between the end transverse sealing means for the zipper stripand the blade for the bags.

[0031] Alternatively described the application provides a form-fill-sealmachine comprising means for moving a web of packaging material throughthe machine according to a process path from a web supply side and meansfor transforming the web into filled bags, further provided with controlmeans having first means for noticing longitudinal marks on the web andfor measuring the web position, the control means being provided withmeans for storage of data regarding the bag length, the machine beingprovided with an end or turn roll for the web, which is movably arrangedon the machine in web direction and which is adjustable in position inweb direction by means of movement means, the control means beingadapted for controlling the movement means of the end roll for alteringthe length the web has to travel from the supply side to the formingmeans, in response to the data from the bag length input and the firstmeans for noticing longitudinal marks on the web and measuring the webposition.

[0032] Alternatively described the patent application provides aform-fill-seal machine comprising means for moving a web of packagingmaterial through the machine according to a process path from a websupply side and means for transforming the web into filled bags, furtherprovided with control means having first means for noticing longitudinalmarks on the web and for measuring the web speed, the control meansbeing provided with means for storage of data regarding the bag length,the machine being provided with an end or turn roll for the web, whichis movably arranged on the machine in web direction and which isadjustable in position in web direction by means of movement means, thecontrol means being adapted for controlling the movement means of theend roll for altering the length the web has to travel from the supplyside to the forming means, in response to the data from the bag lengthinput and the first means for noticing longitudinal marks on the web andmeasuring the web speed.

[0033] From yet a further aspect the invention provides a form-fill-sealmachine comprising means for moving a web of packaging material throughthe machine according to a process path from a web supply side and meansfor transforming the web into filled bags, further comprising a zipperstrip applicator device having means for supplying a zipper strip foreach bag transverse to the process path and having means for sealing azipper strip to the web for each bag to be made, the machine beingadapted for making the bags with continuous web supply over the formingmeans, the machine being provided with means for keeping the web stillat the location of the sealing means, and with means placed downstreamof the sealing means for forming a buffer web length prior to eachkeeping still and releasing it during keeping the web still. Thus areliable, continuous web supply to the moulding and closing means isensured.

[0034] It is preferred here that the end roll and its movement means area part of the buffer forming means, so that it can be effective in twoways.

[0035] From another aspect the invention provides a form-fill-sealmachine comprising means for moving a web of packaging material throughthe machine according to a process path and means for transforming theweb into filled bags, further comprising a zipper strip applicatordevice having means for supplying a zipper strip for each bag transverseto the process path, which supply means comprise a first and a secondconveyor, which in supply direction of the zipper strip are placed onebehind the other and are both provided with means for retaining thezipper strip during supply, a blade being placed between the first andsecond conveyor for cutting the zipper strip. Both conveyors can bedriven by one single drive, the transfer to the second conveyor forinstance being such that this one runs a little faster than the firstconveyor, so that the zipper strip is stretched during positioning.

[0036] Preferably the first and the second conveyor are positioned tosupport the zipper strip.

[0037] Preferably the retaining means are vacuum means. From a furtheraspect the application provides a form-fill-seal comprising means formoving a web of packaging material through the machine according to aprocess path and means for transforming the web into filled bags,further comprising a zipper strip applicator device having means forsupplying a zipper strip for each bag transverse to the process path,which supply means comprise a conveyor positioned transverse to theprocess path, which is positioned to support the zipper strip and isprovided with means for retaining the zipper strip during the supply andpre-sealing at the lower side of the web. The support of the zipperstrip improves its stability during supply and positioning, so that thezipper strip can be accurately applied.

[0038] It is noted that measures discussed above, such as web sidewatcher, the end roll and the adjustment means for the active length ofthe vacuum band, can be used both in an arrangement with two conveyorsand in an arrangement with one continuous conveyor.

[0039] From a further aspect the application provides a form-fill-sealmachine comprising means for moving a web of packaging material throughthe machine according to a process path and means for transforming theweb into filled bags, further comprising a zipper strip applicatordevice having means for supplying a zipper strip for each bag transverseto the process path, which supply means comprise a conveyor positionedtransverse to the process path, furthermore provided with means forpermanently adhering both the strip members provided with male andfemale parts respectively of the zipper strip, at locations that aresituated at a mutual distance corresponding to the desired length of thecut-off zipper strips to the applied, the adhering means comprising twoadhering members, which engage on both sides of the male and femaleparts to seal them to each other. In this way a bulge in the zipperstrip ends is prevented, which is favourable to the manageability in thefurther process. The so-called “crunching” can now take place with arunning zipper strip. By adapting the control means at the wanted striplength and with the known distance between blade and crunch unit, aswell as with known supply speed of the zipper strip, the correct momentfor crunching can be automatically determined and at that moment thecrunch unit can be activated.

[0040] Preferably two adhering members are positioned to enclose themale and female parts between them during sealing.

[0041] It is further preferred here that the two adhering memberscomprise a rotatable or idle anvil and a sealing arm, particularlyultrasonic sealing arm. The freely rotatable anvil prevents unwantedfrictional forces and the arm is only in contact with the strip whencrunching has to take place.

[0042] From a further aspect the invention provides a form-fill-sealmachine comprising means for moving a web of packaging material throughthe machine according to a process path and means for transforming theweb into a tubular shape, turning it into bags, filling the bags andclosing the filled bags, the means for transforming into the tubularshape comprising longitudinal guides, placed at a mutual distancecorresponding to the zipper strip length, for guiding the tube from thetransformation means to the location of filling. Preferably the fillingmeans comprise a chute, which at the outside is provided withlongitudinal guides. Thus it is prevented that the tubular web twistsand the zipper strip would not lie correctly any more and no goodtransverse seal could be made. Because of the longitudinal guides thelargest circumferential size of the chute is not changed, but the stripslie within said circumferential size.

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The inventions will be elucidated on the basis of a number ofexemplary embodiments shown in the attached figures, in which:

[0044]FIG. 1 is a form-fill-seal machine according to the invention inside view;

[0045]FIG. 2 is a view in perspective of the form-fill-seal machine ofFIG. 1, obliquely from its front side;

[0046]FIG. 2A is a detail of the form-fill-seal machine of FIG. 2;

[0047]FIG. 3 is a view in perspective at the rear side of theform-fill-seal machine of the FIGS. 1 and 2;

[0048] FIGS. 4A-D show a zipper strip applicator device of theform-fill-seal machines of FIGS. 1-3, in consecutive stages of use;

[0049] FIGS. 5A-C are some details of the means for adjusting the activelength of the zipper strip applicator device;

[0050]FIG. 6 schematically shows a cross-section of a part of the zipperstrip applicator device of the FIGS. 4A-D;

[0051]FIGS. 7A and 7B show a cross-section and a top view, respectively,of a so-called crunch unit for use in a form-fill-seal machine having azipper strip applicator device; and

[0052]FIGS. 8A ad 8B show a schematic view in perspective of the courseof a foil web to and about a form shoulder with consecutive filling tubein a form-fill-seal machine; and a cross-section of said filling tube,respectively.

DETAILED DESCRIPTION OF THE DRAWINGS

[0053] The form-fill-seal machine 1 shown in FIGS. 1-3 comprises achassis or frame 2, on which various parts and control means have beenarranged to manufacture a series of bags 6 b filled with bulk goods,such as foodstuffs, but also inedible bulk goods, from a foil web 6,that is supplied on a roll 4.

[0054] On frame 2 outriggers 3 are provided, in which a transverse axis5 can be supported. On the axis 5 a roll 4 of foil web 6 has beenplaced.

[0055] For reasons of simplicity a number of parts in process directionwill be named. The foil web 6 is guided about a number of balancer rolls7′, which also ensure that the foil web is locally at the wantedtension, and a number of rolls 7.

[0056] After some rolls 7 and 7′ have been passed, the web 6 passes anincremental encoder 15, and after that over a zipper strip applicatordevice 11 and therewith below a pre-seal unit 12. The zipper stripapplicator device 11 supplies the zipper strip, as will be discussedfurther, in the direction transverse to the process path of the web 6.The pre-seal unit 12 secures the zipper strip to the foil web 6 by meansof applying heat and pressure, so that the zipper strip is taken alongin a reliable manner to the station where the bags are finally formedand closed.

[0057] Downstream of it a web edge follower 18 is positioned, which,with transmitter and receiver that at that side are situated on bothsides of the foil web, acoustically notices where—considered intransverse direction—the foil web material is situated and where it isnot, and thus notices the position of the foil web edge.

[0058] Downstream of it a photo cell 14 is situated, the position ofwhich is adjustable in transverse direction, and which is designed tonotice the tracer spots 40 on the foil web.

[0059] Next the web arrives at the location of a web length manipulator13, which is provided with a bearing roller 7 a which is bearing mountedin slots 70 and which can be moved in the direction D by means ofspindle motor 71 and which takes up a position calculated by a generalcontrol device (not further shown) of the machine.

[0060] After that the foil web continues in the direction C, in order tobe guided downwards past incremental encoder 16, and then subsequentlyupwards again past tracer spot photo cell 17, also shown in FIG. 2A.

[0061] Subsequently the foil web 6 arrives at a form shoulder 8, wherethe foil web is transformed into a tubular shape 6 a. The form shoulder8 surrounds a filling tube 9, which at the upper end is provided with acharging funnel 19 for the bulk goods. Usually the bulk goods aredischarged batch-wise into the funnel 19.

[0062] The foil tube 6 a is sealed in longitudinal direction by means ofvertical longitudinal sealing bar 22. Vacuum bands 20 are positioned onboth sides of the foil tube 6 a, which bands do not only ensuretransport of the foil tube 6 a, but the entire transport of the foil webthrough the device 1.

[0063] At the downstream end of the filling tube 9 transverse weldingrods 21 a, 21 b are arranged, that can be moved towards each other tosimultaneously make the upper seam of a lower bag and the lower seam ofa subsequent bag positioned above it, and simultaneously separate bothbags from each other. The zipper strip is also finally sealed to thefoil here. Moreover a cutting blade is present there for separating thebags from each other between two longitudinal seals.

[0064] For the control of the various parts and the mutual adjustment ofthem a control unit is included that is not further shown, to whichoperation panel 10 is also connected.

[0065] Referring to FIG. 4A the zipper strip applicator device 11 willnow be discussed. The zipper strip applicator device 11 is mounted onoutriggers 30 a, 30 b, which can be retracted and extended in thedirection D from the frame 2 of the form-fill-seal machine 1. All thisis schematically shown, the outrigger 30 a supporting on bracket 32(outrigger 30 b can be supported in a similar manner), and can besecured in the operational position by means of turning knob 33. Thiscan also take place by means of snap means that are not further shown.Means that are not further shown are provided to inform the control unitof the machine 1 of the operational position of the device 11. Tofacilitate the retraction and extending, respectively, of the device 11it is provided with handle 38.

[0066] Between the outriggers 30 a, 30 b a transverse frame 31 issituated, on which spindle motor 39 is attached with one end. With theother end the spindle motor is attached to frame part 31 a, this inorder to be able to move it in the direction E and secure it in a chosenposition when operated, which then also takes place by the spindle motor39.

[0067] The frame part 31 a is also provided with a outrigger 37, onwhich a support 34 with a passage slit 36 for a zipper strip 25 isarranged. Furthermore idle support rolls 35 a and 35 b are provided onthe passage 36, for guiding the zipper strip 25 in the supply. Themachine 1 may further be provided with means for keeping the strip 25tensionless, so that sufficient supply length is available for thedevice 11, without the zipper strip 25 having to be pulled from a stockroll by the device 11 itself.

[0068] The frame part 31 a is also provided with two vacuum devices 41and 42, which in longitudinal direction have been placed adjacent toeach other and between which cutting blade 51 is placed, which cuts inupward direction. Above the blade 51 an anvil that is not furtherindicated is placed.

[0069] The vacuum device 41 is limited in upward direction by a firstvacuum band 43, and the vacuum device 42 is upwardly limited by secondvacuum band 44. Both bands 43 and 44 are endless and are driven by meansof their own servo motors 48, 49, that can be driven independent fromeach other by the control device accommodated in the machine 1.

[0070] In the FIGS. 5A, 5B and 5C some means for adjusting the activelength of the second vacuum conveyor belt 44 are elucidated.

[0071] As can be seen in FIG. 5A, the pre-seal station 18 is situated ata short distance above the zipper strip applicator device 11. Thepre-seal device 18 is provided with a holder 81, in which a pre-seal rod82 is accommodated.

[0072] As also clearly shown in FIG. 5B the zipper strip applicatordevice 11 with portion 31 a is provided with an endless vacuum band 44,that is provided with vacuum apertures 44 a. The direction of transportof the path C, for that matter, is inverted to the one of FIG. 6 yet tobe discussed. This means that the strip 25 c to be pre-sealed of thezipper strip 25 is situated at the (downstream) left side, in thedrawing above a silicone strip 50, which serves as anvil for the weldingrod 82 (in direction F, FIG. 6). The strip 50 is supported on portion96, that can be taken away to permit replacement of the vacuum band 44.

[0073] In the upper course of the vacuum band 44 it runs overlongitudinal support 90, which is provided with a series of vacuumapertures 91 extending over its entire length. Said vacuum apertures 91are in flowing contact with a same series of passages 92 that have beenmade in the block 31 a. The passages 92 are in connection with theseries of apertures 94 that have been arranged in the wall of the vacuumtube 93 that is rotatably accommodated in the block 31 a. In a mannerthat is not further shown, said vacuum tube 93 is in connection with avacuum source in the machine 1.

[0074] As can be seen in FIG. 5C, in which six rotation positions of thevacuum tube 93 are shown, the wanted series of apertures 94 can bebrought in front of the passages 92, by rotation of the tube 93 by meansof the adjustment button 74 that can be reached well by the operatorwhen the device 11 is in the taken-out position. It will be understoodthat only the passages 92 and thus the apertures 91 that will beconnected with the apertures 94, will also be active. The active lengthof the vacuum band 44 will then correspond to the distance L3 of theseries of apertures 94, then to be calculated from the blade 51.

[0075] At the in relation to the process direction C upstream side ofthe bands 43 and 44, a strip 45 is attached to the frame part 31 a,which is provided with regularly spaced apart protrusions 46. Theprotrusions 46 are designed to engage between the strips forming thezipper strip 25, provided with male and female parts of the couplingrespectively, extending up to said male and female parts, and keepingthe zipper strips stretched particularly in the horizontal plane duringtransport of the zipper strip, the friction being minimized by therecesses between the teeth 46. Reference can also be made to thecross-section according to FIG. 6.

[0076] In an alternative—or further developed—embodiment a so-calledcrunch unit can be placed between the passage 34 and the frame 31/31 a.Said unit is further only schematically shown in the FIGS. 7A and 7B.The so-called crunching of a zipper strip is done to attach bothcooperating strips 25 a and 25 b/c respectively to each other, so thattheir position one to the other in a bag is maintained therein evenafter opening the zipper strip and reclosing the zipper strip is easy.Usually this crunching takes place by means of sealing means that engagethe zipper strip at the location of the male and female parts, above andunderneath, and seal them under pressure. The drawback thereof is thatthe material bulges sidewards. Said bulges may cause problems duringfurther transportation of the zipper strip over the guides in themachine.

[0077] Another drawback is that the location where the crunching unit isactive has to be accurately adjusted to the location of the blade thatcuts off the zipper strips.

[0078] With the crunching unit according to the invention, positioned tobe active in a plane transverse to the operation plane of the knowncrunch units, said problems are solved. In the example of the FIGS. 7Aand 7B there is question of a rotating anvil 61, that is positionedimmediately along/against the path of movement of the male and femaleparts. Because the anvil 61 rotates along with the zipper strip acounter plane is provided for the crunching in a friction-poor manner.

[0079] The crunching itself takes place by means of arm 62, which forinstance is pneumatically and reciprocally moveable in a directiontransverse to the zipper strip between a inoperative position and anoperative position, and may extend in the space between the flanges 25 aand 25 b of the zipper strip 25. When activated the arm will vibrateultrasonic. Because crunching can now take place on a running zipperstrip it is no longer necessary to adjust the distance of the crunchingunit to the blade at the zipper strip length. It is sufficient to entersaid distance once as a data in the control unit. Said unit can thendetermine the moment of activation of the arm 62, also on the basis ofthe data regarding the supply speed of the strip and the wanted zipperstrip length, and control it.

[0080] During sideward crunching the material can only flow away inlongitudinal direction of the zipper strip, which is not disadvantageousfor the further transport of the zipper strip. There are no bulges thenthat render the guiding of the zipper strip difficult.

[0081] In the FIGS. 8A and 8B a further aspect of the device accordingto the application is shown, destined for use in making bags using asquare or rectangular filling/form tube. The web 6 is transformed intotube 6 a by form shoulder 8, the zipper strip 25 being situated at therear side. In order to rule out any torsion of the tube 6 a duringdownward transport, the filling tube 9 is provided with walls 26 c, 26a, 26 b and 26 d, the walls 26 a and 26 b extending beyond the wall 26 dto define a continuous accommodation space or duct 26 e for the zipperstrips 25. When another bag width and zipper strip length has to beused, a filling tube/form shoulder assembly adapted to those sizes canbe placed. In FIG. 8A it can be seen that the filling tube 9 forms aunit with a mounting plate 27 that is attached in the frame 2 by meansof bolts 28.

[0082] The form-fill-seal machine 1 shown in the FIGS. 1-3 works asfollows. Via the control means and the operation panel 10 a number ofbasic data are entered by the operator. The most important of thembeing: type of bag, bag length and bag width, and the type of thelongitudinal seal. After that the control means indicate via theoperation panel at which position the roll of foil 4 has to be placed atthe support shaft 5, so that later the packaging material has thecorrect position with respect to the form shoulder 8. To that end thesupport shaft 5 is provided with a calibration. The control unitcontrols the motor 39 based on the data regarding the bag width and thetype of bag to bring the device 11 at the wanted location in widthdirection. This takes place without foil and is the so-called widthpositioning.

[0083] The operator places the roll of foil 4 at the rear side of A ofthe machine 1. Foil web material 6 is manually pulled from the roll andguided about the various end rolls 7, about the form shoulder 8 andabout the filling tube 9, until the foil is at least in engagement withthe vacuum conveyor belts 20.

[0084] Subsequently the machine 1 is left to run for awhile. During thisrunning the tracer spots 40 are noticed by means of a photo cell 17. Theposition of the photo cell 17 and the encoder 16 with respect to thetransverse sealing jaws 21 a, 21 b are exactly known in the controldevice, wherein the tracer spot distance t has also been entered viapanel 10. The tracer spot distance t corresponds to the bag length.Between the tracer spots a printing pattern is present. The transverseseals are of course not meant to be made through the printing pattern.

[0085] By means of the control device, based on the data mentioned, andby means of the vacuum bands 20, the correct length of foil istransported and positioned such with respect to the transverse sealingjaws 21 a/b that, after said jaws close, the printing pattern on theready packaging, is correct. The packaging machine runs in so-called“photo cell”.

[0086] After the machine 1 runs “in photo cell” the distance between thetracer spot and the cutting line is manually measured on a package made.Said value (L1) is as yet entered via the operation panel 10 into thecontrol means. After that the operator presses a key (trial cycle). Themachine 1 then makes a packaging, the photo cell 14 and the encoder 15at the rear side of the machine 1 becoming active. The encoder 15 thenmeasures the web length that passes over a measurement time and thephoto cell 14 registers the moment the tracer spot passes by the photocell 14. When the foil transport stops again, the transverse seal jawsclose and the cutting blade cuts off the packaging, the encoder 15 hasmeasured what length of web lies between the position of the tracer spot40 at that moment and the position of the tracer spot when it wasnoticed by the photo cell 14. Said distance L2 is compared with thedistance L1. Based on the difference between L1 and L2, the physicaldistance between the photocell 14 and the position of the pre-seal unit12, the bag length and the physical position (distance) of the post sealjaw placed in both transverse jaws for the zipper strip to the packagingwith respect to the cutting blade that is present in the transversesealing jaws, the control means control the spindle motor 71 to move(here in horizontal direction, guided by the horizontal slits 70) thebuffer roll 7 a such that the zipper strip is sealed in the packagingmaterial at the correct position, seen in web direction, with respect tothe tracer spot by means of pre-seal unit 12.

[0087] By thus not using the physical distance between the transversesealing jaws 21 a,b and the position of the pre-seal unit, the controlsystem is insensitive to errors caused by elastic foils, as a result ofwhich the theoretical distances might not correspond to the actualdistances, as well as length deviations as a result of the presence ofmany pre-sealed zipper strips on the web. Positioning the zipper strip25 with respect to the tracer spot 40 is actually taking place by meansof an autonomous system at the rear side A of the machine.

[0088] The further adjustment of the zipper strip applicator device 11itself takes place as follows. The device 11 is entirely pulledbackwards a length out of the machine by the operator. As a result amaximum accessibility for entering the zipper strip is created. Testscan then also be run in the device 11 in order to see whether all itsfunctions are working. The zipper strip 25 is manually guided throughthe passage slit 36, and laid on the vacuum band 43, the teeth 46extending between the male and female part strips. Subsequently thelength of engagement is adjusted by the second conveyor 44 via theadjustment button 74, with which the series of apertures accompanyingthe active length in question can be brought into active connection withthe vacuum band and the vacuum source. Via sensor 73 the active lengthis noticed and passed on to the control means, and shown on theoperation panel 10. When testing the positioning of the zipper strip 25by means of the second conveyor 44 use can be made of the calibration47, extending from the blade and indicating how long the cut-off zipperstrip portion is.

[0089] After said adjustment is completed the operator will push backthe device 11 into the machine, a correct positioning of the device 11again being noticed by a sensor that is not further shown, as a resultof which the machine is released by the control means at this point.

[0090] After a certain period of test driving, the control meansensuring a correct adjustment, the machine 1 is ready for theform-fill-seal process of the bags. The web 6 here runs in the directionC, the zipper strips 25 being applied in the first station at thelocation of the applicator device 11.

[0091] The application of zipper strips 25 takes place as follows. Thezipper strip 25 is retained by means of the first conveyor 43 by vacuum,and transported in the direction G (see FIG. 4B). The remaining portionof the zipper strip 25 is in stock in a long loop, so that no particularcounter forces have to be overcome. As a result no slipping will arisebetween the zipper strip 25 and the conveyor 43. During transport theteeth 46 extend between both flanges 25 a and 25 b of the zipper strip25. As a result the disadvantageous results of the undulation in thezipper strip 25 are counteracted, and the—particularly in the horizontalplane-stretched transport of the zipper strip 25 is improved.

[0092] When the leading end of the zipper strip 25 arrives at the secondconveyor 44, said end is engaged by the vacuum of said conveyor. Bymeans of the servo motors 48 and 49 controlled by the control device,both conveyors 43 and 44 are driven, at the same speed, or the secondconveyor at a little higher speed to keep the zipper strip stretched atall times. A resolver present in the servo motor 48 together with alarge transmission ratio ensures that a very accurate length of zipperstrip is discharged to the second conveyor 44. As soon as the correctlength has been reached the blade 51 is activated. The first conveyor 43can be considered a supply conveyor and a length/dosing conveyor.

[0093] During cutting the vacuum is maintained in both conveyors.Subsequently the servo motor 49 is activated again, and the conveyor 44is driven in the direction G, to bring the cut-off zipper strip 25 at acorrect position in transverse direction of the web 6 and retain itunder it. A resolver present in the servo motor 49 together with a largetransmission ratio ensures that the cut-off length of zipper strip ispositioned accurately. The pre-seal unit 12 is then operated to attachthe flange 25 c to the foil web 6. The silicone strip 50 here serves asanvil.

[0094] The pre-seal unit 12 attaches the zipper strip 25 at the upperside of the foil web, which later on forms the inner side of the bag.The seal beam 81/82 of the seal unit 12 is pneumatically driven. Theposition of the seal beam as well is adjustable in transverse direction.Depending on the width of the zipper strip 25 that has to be sealed in,another seal beam is placed in the holder.

[0095] When during the operation of the machine 1 the foil web shouldslide in transverse direction this is noticed by the web side sensor 18.This observation is converted by the control device into a proportionaldrive of the spindle motor 39.

[0096] Alternatively it can be provided that the control device insteadof the spindle motor 39 then controls the servo motor 49 in a changedmanner. In that case the adjustment of the active length of the band 44will of course also have to be sufficient to that end.

[0097] It is noted that the control device also during normal operationkeeps on noticing the positions of the tracer spots 40 by means of theaforementioned sensors. It occurs that the distance one to the other ofthe tracer spots 40 varies on a roll. In that case automatic levellingwill take place in the web length between the sensor 14 and thetransverse seal jaws 21 a,b by operating the spindle motor 71 and thusthe movement of the roll 7 a. This then is the length-following system.

[0098] The form-fill-seal machine 1 will in general be operative insteps. However, there are continuous web transporting form-fill-sealmachines. The provisions according to the invention can be used in themas well, particularly advantageous use being made of the arrangementwith the moveable buffer roll 7 a. The machine 1 is here provided with abrake 80 for the web 6, to keep it entirely still at the location of thezipper strip applicator device 11. A zipper strip can be applied in avery controlled manner. After that the operation of the brake 80 isstopped by the control device and web transport takes place again, untilthe next zipper strip has to be applied.

[0099] During the web transport, the control device will operate thespindle motor 71 to move the roll 7 a from the front to the rear. As aresult the web length is increased there, and namely by a doubledistance compared to the distance of movement of the roll 7 a. Thebuffer length thus created is equal to the web length that should betransported at a normal operation when the brake 80 would not beactivated. For an uninterrupted, continuous operation, sufficient webmaterial should then at all times be in stock for the vacuum conveyorbelts 20 at the front of the machine 1.

1. Form-fill-seal machine comprising means for moving a web of packagingmaterial through the machine according to a process path and means fortransforming the web into filled bags, furthermore comprising a zipperstrip applicator device having means for supplying a zipper strip foreach bag transverse to the process path, which supply means comprise afirst and a second conveyor, which in the supply direction of the zipperstrip are placed one behind the other and are both provided with meansfor retaining or engaging the zipper strip during supply, a blade beingplaced between the first and the second conveyor for cutting the zipperstrip, wherein the means for retaining or engaging the zipper stripinclude vacuum means and retain or engage the zipper strip at variouslocations along the length of the zipper strip.
 2. Form-fill-sealmachine according to claim 1, wherein the first conveyor and the secondconveyor are driven by one single drive.
 3. Form-fill-seal machineaccording to claim 1, wherein the first conveyor and the second conveyorare positioned below the process path of the web to support the zipperstrip.
 4. Form-fill-seal machine according to claim 1, provided withmeans for adjusting the active length of the vacuum means for the secondconveyor.
 5. Form-fill-seal machine according to claim 4, the controlmeans being provided with means for comparing an entered zipper striplength and the position in transverse direction to the web and theadjusted length of the vacuum means, and of means for releasing thedrive of the machine based on the outcome of said comparison. 6.Form-fill-seal machine according to claim 5, the means for adjusting theactive length of the vacuum means for the second conveyor comprising atube to be connected to a vacuum source, which tube in its circumferenceis provided with series of apertures of different length extending intube direction, and which is rotatable in an adjustable manner to let aselected series of apertures form the connection between the aperturesin the vacuum band and the tube.
 7. Form-fill-seal machine according toclaim 1, provided with control means for the first and second drivemeans and the blade, the control means being adjusted to consecutivelyoperate the first drive means to transfer a predetermined length ofzipper strip to the second conveyor, to subsequently operate the bladeand then operate the second conveyor for positioning the cut-off zipperstrip portion transverse to the web.
 8. Form-fill-seal machine accordingto claim 7, the control means being adjusted to let both conveyors moveat the same speed during the supply of the length of zipper strip. 9.Form-fill-seal machine according to claim 8, the retaining means of thefirst and the second conveyors being controlled by the control means.10. Form-fill-seal machine according to claim 9, the control means beingadjusted for continuously activating the engaging means of the first andsecond conveyors.
 11. Form-fill-seal machine comprising means for movinga web of packaging material through the machine according to a processpath and means for transforming the web into filled bags, furthermorecomprising a zipper strip applicator device having means for supplying azipper strip for each bag transverse to the process path, which supplymeans comprise a first and a second conveyor, which in the supplydirection of the zipper strip are placed one behind the other and areboth provided with means for retaining or engaging the zipper stripduring supply, a blade being placed between the first and the secondconveyor for cutting the zipper strip, wherein the first conveyor andthe second conveyor are positioned below the process path of the web tosupport the zipper strip.
 12. Form-fill-seal machine according to claim11, wherein the means for retaining or engaging the zipper strip includevacuum means.
 13. Form-fill-seal machine according to claim 12, providedwith means for adjusting the active length of the vacuum means for thesecond conveyor.
 14. Form-fill-seal machine according to claim 13, thecontrol means being provided with means for comparing an entered zipperstrip length and the position in transverse direction to the web and theadjusted length of the vacuum means, and of means for releasing thedrive of the machine based on the outcome of said comparison. 15.Form-fill-seal machine according to claim 14, the means for adjustingthe active length of the vacuum means for the second conveyor comprisinga tube to be connected to a vacuum source, which tube in itscircumference is provided with series of apertures of different lengthextending in tube direction, and which is rotatable in an adjustablemanner to let a selected series of apertures form the connection betweenthe apertures in the vacuum band and the tube.
 16. Form-fill-sealmachine according to claim 11, provided with control means for the firstand second drive means and the blade, the control means being adjustedto consecutively operate the first drive means to transfer apredetermined length of zipper strip to the second conveyor, tosubsequently operate the blade and then operate the second conveyor forpositioning the cut-off zipper strip portion transverse to the web. 17.Form-fill-seal machine according to claim 16, the control means beingadjusted to let both conveyors move at the same speed during the supplyof the length of zipper strip.
 18. Form-fill-seal machine according toclaim 17, wherein the first conveyor and the second conveyor are drivenby one single drive.
 19. Form-fill-seal machine according to claim 16,the retaining means of the first and the second conveyors beingcontrolled by the control means.
 20. Form-fill-seal machine according toclaim 19, the control means being adjusted for continuously activatingthe engaging means of the first and second conveyors.
 21. Form-fill-sealmachine comprising means for moving a web of packaging material throughthe machine according to a process path and means for transforming theweb into filled bags, furthermore comprising a zipper strip applicatordevice having means for supplying a zipper strip for each bag transverseto the process path, which supply means comprise a first and a secondconveyor, which in the supply direction of the zipper strip are placedone behind the other and are both provided with means for retaining orengaging the zipper strip during supply, a blade being placed betweenthe first and the second conveyor for cutting the zipper strip, whereinthe first conveyor and the second conveyor are similar and driven by onesingle drive and the means for retaining or engaging the zipper stripinclude vacuum means.
 22. Form-fill-seal machine according to claim 21,provided with means for adjusting the active length of the vacuum meansfor the second conveyor.
 23. Form-fill-seal machine according to claim22, the control means being provided with means for comparing an enteredzipper strip length and the position in transverse direction to the weband the adjusted length of the vacuum means, and of means for releasingthe drive of the machine based on the outcome of said comparison. 24Form-fill-seal machine according to claim 23, the means for adjustingthe active length of the vacuum means for the second conveyor comprisinga tube to be connected to a vacuum source, which tube in itscircumference is provided with series of apertures of different lengthextending in tube direction, and which is rotatable in an adjustablemanner to let a selected series of apertures form the connection betweenthe apertures in the vacuum band and the tube.
 25. Form-fill-sealmachine according to claim 21, at least the second conveyor being placedbelow the web.
 26. Form-fill-seal machine according to claim 21,provided with control means for the first and second drive means and theblade, the control means being adjusted to consecutively operate thefirst drive means to transfer a predetermined length of zipper strip tothe second conveyor, to subsequently operate the blade and then operatethe second conveyor for positioning the cut-off zipper strip portiontransverse to the web.
 27. Form-fill-seal machine according to claim 26,the control means being adjusted to let both conveyors move at the samespeed during the supply of the length of zipper strip. 28.Form-fill-seal machine according to claim 27, the retaining means of thefirst and the second conveyors being controlled by the control means.29. Form-fill-seal machine according to claim 28, the control meansbeing adjusted for continuously activating the engaging means of thefirst and second conveyors.
 30. Form-fill-seal machine comprising meansfor moving a web of packaging material through the machine according toa process path and means for transforming the web into filled bags,further comprising a zipper strip applicator device having means forsupplying a zipper strip for each bag transverse to the process path,which supply means comprise a conveyor positioned transverse to theprocess path, which is positioned to support the zipper strip and isprovided with vacuum operated means for retaining the zipper stripduring the supply and pre-sealing at the lower side of the web.